LT spice is excellent. I've used them all over the decades back to the very early days of BerkleySpice. Simple thing to keep in mind: no cpu can keep up computationally if you throw a huge number of nodes at it and if it can't converge on an expected result. Keep your sims simple and break them down to the simplest elements. Do multiple sims to validate a design or break it into small parts as you would do in a real hardware endeavor.
Remember, its not the size of the tool or the power of the tool, its how you use it.
However, that said, it wont matter in the final analysis anyways because you are working with virtual components that rarely exist in reality, so your result will be flawed in some way or other. Sim tools are like aspirin or pornography, they do little to help or address root cause but are very handy at times. Lecture is adjourned.